The question is who is at fault? The guy who bumped the thread 1st sirminesalot? All of them? Guys who kept bumping?
I probably wouldn't blame the members who posted after the thread got bumped, because they might not have noticed what the date was in the OP. I've done that quite a few times by accident, and it's a mistake anyone can make--so IMO the blame falls squarely on the person who actually bumped the thread.
But then you should be sure who bumped the thread, as in this case the person who bumped it ,removed the post and now everyone will think the 2nd person is actually the first person who bumped it. (which is actually not true).
The post disappeared, modlog doesn't show anything for the user or topic so it was deleted by the user, I can guess why.....but ...